Stemple was a married kids’ soccer coach in 1996 when he had an affair and enlisted his girlfriend’s 16-year-old cousin to help him kill his wife of 11 years, according to evidence presented at his 1997 trial.

Trisha Stemple, 30, was beaten, run over with a pickup truck and left on the side of a road beside her car, whose tire was punctured with a drill to make the crime appear to be random carjacking, testimony showed.

Timothy Stemple might have collected on a $950,000 life insurance policy, but his teen-age accomplice testified against him in exchange for a life prison term, court testimony showed.

The 30-year-old woman was beaten with a plastic-covered baseball bat and run over by a pickup truck October 24, 1996, along a Tulsa highway.

Her husband maintained his innocence throughout the trial and appeals process.

And at a clemency hearing last month, Timothy Stemple, 46, declined to talk about the case, saying it wasn’t the appropriate forum.

Murder: Timothy Stemple, right, enlisted his girlfriend’s 16-year-old cousin to help him kill his wife of 11 years Trisha, left

Stemple’s execution is the first of three scheduled over the next two months in Oklahoma.

Last month, Department of Corrections officials said the state has four doses left of the lethal injection drug pentobarbital, an anaesthetic that manufacturers have objected to selling for use in executions.

Stemple’s accomplice, Terry Hunt, told The Associated Press during a prison interview Sunday that he was disappointed Stemple didn’t confess when given the opportunity at the clemency hearing.

Guilty: Stemple was convicted of his wife’s murder in 1997 and sentenced to death

‘I’m not innocent and Shaun is not innocent,’ said Hunt, who’s in prison in Hominy serving a life sentence.

Hunt is the cousin of Dani Wood, who was having an affair with Timothy Stemple.

Hunt’s testimony that the crime was brutal, with Trisha Stemple being conscious during much of the attack, was a factor that helped prosecutors secure the death penalty for Stemple.

Hunt struck the woman with a bat twice and her husband hit her in the back of the head about 20 to 30 times, according to Hunt’s testimony.

Hunt said Stemple tried to drive over his wife’s head with the pickup truck.

Hunt tried to place a wheel on her chest.

Following the initial attack, she managed to drag herself onto grass along the highway after they drove away.

In his testimony, Hunt said they returned and struck her with the truck, traveling about 60 mph.

A forensic expert consulted by Timothy Stemple’s family said the wife’s injuries were consistent with being hit by a vehicle and run over but that there’s no evidence she was beaten.

The medical examiner first thought she died after being hit by a car, but there was ‘no primary point of impact below the knees as is usual in the typical auto-pedestrian collision,’ prosecutors said in a report in the case.